Exceptions are a means of breaking out of the normal flow of control of a code block to handle errors or other exceptional conditions. Pros: The control flow of normal operation code is not cluttered by error- error- handling code. It also allows the control flow to skip multiple frames when a certain condition occurs, e.g., returning from N nested functions in one step instead of having to carry-through error error codes. Cons: May cause the control flow to be confusing. Easy to miss error cases when making library calls. 4 Decision: Exceptions must follow certain conditions: • Raise exceptions like this: raise

Cahill, Uwe Röhm, Alan D. Fekete: Serializable isolation for snapshot databases. SIGMOD 2008  Data Flow Systems  #10.1 Matei Zaharia et al.: Resilient Distributed Datasets: A Fault-Tolerant Abstraction #17.1 Lasse Thostrup, Jan Skrzypczak, Matthias Jasny, Tobias Ziegler, Carsten Binnig: DFI: The Data Flow Interface for High-Speed Networks. SIGMOD 2021  #17.2 Clemens Lutz, Sebastian Breß, Steffen Zeuch

g has to be careful or it may not clean up properly. • More generally, exceptions make the control flow of programs difficult to evaluate by looking at code: functions may return in places you don’t expect someone casually brows- ing the code base will be able to understand the error messages or trace the flow of a function they want to call. If you’re using recursive template instantiations or type lists or principle is: The more code that fits on one screen, the easier it is to follow and understand the control flow of the program. Of course, readability can suffer from code being too dense as well as too spread

logical consequence)  #2 Read Fully  Read and annotate issue, don’t fix immediately (destroys the flow)  Take annotated document and fix issues  #3 Ask Big Questions  Pitfall: Being overly focused